<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title></title>
  <script src="https://unpkg.com/react@16/umd/react.development.js"></script>
  <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
  <!-- 生产环境中不建议使用 -->
  <script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
</head>

<body>
  <!-- 容器 -->
  <div id="test"></div>

  <script type="text/babel">
   class Demo extends React.Component {
      /**
       React.createRef调用后可以返回一个容器，该容器可以存储被ref所标识的节点，该容器是”专人专用“的
       */
      myRef = React.createRef()
      myRef2 = React.createRef()
      showData = ()=>{
        console.log("this.myRef",this.myRef);
        console.log("this.myRef.current",this.myRef.current);
        alert(this.myRef.current.value)
      }
      showData2 = ()=>{
        alert(this.myRef2.current.value)
      }
      render(){
        return (
          <div>
            <input ref={this.myRef} type="text" placeholder="点击按钮提示数据" />&nbsp;
            <button onClick={this.showData}>点我提示左侧的数据</button>&nbsp;
            <input ref={this.myRef2} onBlur={this.showData2} type="text"placeholder="失去焦点提示数据" />
            </div>
        )
      }
   }
   
    //2.渲染虚拟DOM到页面
    ReactDOM.render(<Demo a="1" b="2"/>, document.getElementById("test"))
  </script>

</body>

</html>
